Căn bậc hai của số $a =  - 3$ là:

$7$

$- 4$  

$- 3$  

$3$

$\overline z  = z$       

$\left| {\overline z } \right| = \left| z \right|$             

$\left| z \right| + \left| {\overline z } \right| = 0$

$\left| {\overline z .z} \right| = 0$

$b = 0.$

$b =  - 6$.

$b =  - 3i$.

$b =  - 3$.

$\left| {{z_1} - {z_2}} \right| = \sqrt {17} .$

$\left| {{z_1} - {z_2}} \right| = \sqrt {15} .$

$\left| {{z_1} - {z_2}} \right| = \sqrt 2  + \sqrt {13} .$

$\left| {{z_1} - {z_2}} \right| = \sqrt {13}  - \sqrt 2 .$

$z = 4 - i;z =  - 5 + 2i$  

$z = 4 - i;z =  - 5 - 2i$

$z = 4 + i;z =  - 5 - 2i$

$z = 4 + i;z =  - 5 + 2i$

${\left| z \right|_{\min }} = 2.$

${\left| z \right|_{\min }} = 1.$

${\left| z \right|_{\min }} = \sqrt 2 .$

${\left| z \right|_{\min }} = \dfrac{1}{{\sqrt 2 }}.$